INT B3 - ZIPKEY v2.0+ - DETERMINE STATE FOR AREA CODE                           
	AH = 80h
	BX = telephone area code (decimal)
Return: CF clear if successful
	    AL = ZIPKEY state code
	    DX = first ZIP region for state (03E8h if Canada)
	    CX = number of ZIP regions in state
	CF set on error
	    AL = FFh
	    DX = 03E9h